Description
Astylosternus schioetzi is a stocky-bodied West African frog in which males range from 41.5 - 43.5 mm in snout-vent length with an average of 42.5 mm. This species has a square head with a short snout and a prominent, rounded canthus rostralis. The tympanum to eye ratio is 66.67%. The dorsal integument is wrinkled and granulated on the dorsum and flanks, but mostly smooth on the head and limbs. The lateral-dorsal fold is well developed. The anterior limbs have prominent, subconical and ovoid tubercles at the base of the fingers, whereas the hind limbs have prominent subarticular tubercles. The toe tips are short and not dilated. The webbing is very limited but thick, giving the impression that the toes are more connected (Amiet 1977). The last phalanx of toes II - V is recurved and can protrude through the ventral skin of the toe, likely used to defend the frog by scratching potential predators (Blackburn et al. 2008). The males during breeding season have a single nuptial pad and no gular spines (Amiet 1977).

The dorsal coloration is beige, gray or yellow with a paler area with large subcircular brown or black markings. On the top of the head, there is an intraocular design forming a pair of triangle or trapezoidal shapes extending from the center of the head to the eye on each side. The ventral coloration is pale yellow and the bottom of the legs have a darker brown color, sometimes with the presence of a paler medial region. The thighs have 3 - 5 transverse black or brown bands (Amiet 1977).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Cameroon

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (1 records).

This species is found in lowland southwestern Cameroon (Amiet 1977; Channing and Rödel 2019), where it is associated with streams and swampy forested areas. Its presence has been confirmed through surveys near Edéa: particularly near Apouth (20 km south of Edéa) and Koupongo (21 km north of Edéa; Amiet 1977).

Life History, Abundance, Activity, and Special Behaviors
According to Amiet (1977), A. schioetzi is very rare.

Adults are nocturnal with reproductive seasons in April, May, and November (Amiet 1977). During the breeding season, male are found in small streams or swampy areas (Channing and Rödel 2019). The advertisement call is described as "Kouli" or "Kou" over a period of 45 seconds with 3 notes per second (Amiet 1977).

Trends and Threats
The population trend is decreasing due to habitat loss and degradation caused by clearance for agricultural land, human settlements and logging (IUCN 2021).

Comments
Preliminary genetic studies have found two clades in the genus, a West African clade and a Central African clade (Portik et al. 2019). Astylosternus schioetzi is likely found in the Central African clade (Allen et al. unpubl data).

References

Amiet, J.-L. (1977). ''Les Astylosternus du Cameroun (Amphibia Anura, Astylosterninae).'' Annales de la Faculté des Sciences de Yaoundé, 23/24, 99-227.

Blackburn, D. C., Hanken, J., Jenkins Jr, F. A. (2008). "Concealed weapons: erectile claws in African frogs." Biology Letters 4, 355–357. [link]

Channing, A., Rödel, M.-O. (2019). Field Guide to the Frogs and Other Amphibians of Africa. Penguin Random House South Africa, Cape Town, South Africa.

Griesbaum, F., Hirschfeld, M., Barej, M. F., Schmitz, A., Rohrmoser, M., Dahmen, M., Mühlberer, F., Liedtke, H.C. Gonwouo, N.L., Doumbia, J., Rödel, M. O. (2019). "Tadpoles of three western African frog genera: Astylosternus Werner, 1898, Nyctibates Boulenger, 1904, and Scotobleps Boulenger, 1900 (Amphibia, Anura, Arthroleptidae)." Zoosystematics and Evolution, 95, 133–160. [link]

IUCN SSC Amphibian Specialist Group. (2017). "Astylosternus schioetzi." The IUCN Red List of Threatened Species 2017: e.T54425A95850221. https://dx.doi.org/10.2305/IUCN.UK.2017-2.RLTS.T54425A95850221.en. Accessed on 01 February 2022.

Portik DM, Bell RC, Blackburn DC, Bauer AM, Barratt CD, Branch WR, Burger M, Channing A, Colston TJ, Conradie W, Dehlin JM, Drewes RC, Ernst R, Greenbaum E, Gvozdík V, Harvey J, Hillers A, Hirschfeld M, Jongsma GFM, Kielgast J, Kouete MT, Lawson LP, Leaché AD, Loader SP, Lötters S, van der Meijden A, Menegon M, Müller S, Nagy ZT, Ofori-Boateng C, Ohler A, Papenfuss TJ, Rößler D, SinschU, Rödel MO, Veith M, Vindum J, Zassi-Boulou AG, McGuire JA (2019). ''Sexual dichromatism drives diversification within a major radiation of African amphibians.'' Systematic Biology , 68(6), 859-875. [link]

Species Account Citation: AmphibiaWeb 2023 Astylosternus schioetzi: Schioetz's Night Frog <https://amphibiaweb.org/species/1490> University of California, Berkeley, CA, USA. Accessed Nov 26, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 26 Nov 2024.

AmphibiaWeb's policy on data use.